A sidelight of North Dakota’s oil/natural gas boom that predates the shale plays by decades is the widespread natural occurrence of shallow-lying gas mixing with groundwater. The state’s Department of Mineral Resources (DMR) conducts an ongoing study that has identified gas in groundwater in 52 of the state’s 53 counties.

“We see shallow gas occurrences across the entire state,” DMR geologist Fred Anderson told NGI’s Shale Daily Tuesday. “They can be somewhat localized depending on the hydro-geologic conditions in that particular area of the state.”

Naturally occurring methane has been found all over, and residents drilling their own water wells often encounter this condition. In the past many residents would pipe the methane to their homes for use in heating and cooking, said Anderson, who has been studying the situation for years.

“We found it in every county we have looked at, and we have looked at 52 of the 53 counties,” he said. The one unaccounted for jurisdiction, a Native American reservation, declined to submit data to the state as it is under federal jurisdiction.

It is unclear if this widespread natural occurrence of the shallow gas is unique to North Dakota. Anderson, who is a native from Minot, ND and has studied groundwater issues for DMR, said he does not know about the national picture, but he would not be surprised if it was widespread in other places.

In North Dakota, the DMR through Anderson’s work, is monitoring and following up on reports from citizens who encounter naturally occurring methane in their groundwater. “The folks who call in have been having this occur for decades, in some cases back to the early part of the 20th Century,” he said.

Residents encountering the gas-water mix are not required to abandon the well or report it to the state, said Anderson, who has been conducting investigations of the geochemical nature of the detected gas. His work is aimed at identifying more precisely how the pockets are formed and in what geologic environment.

“What has usually happened is that most people sign up for rural water when it comes their way and in a lot cases the water wells with gas commingling have been abandoned on their own,” Anderson said. “Our role is just to investigate the interesting geologic conditions that we find to determine how scientifically this plays a role in future resource developments in the state.”

However, he said other agencies governing public health and water quality have specific roles for tracking volumes and safety of groundwater supplies.